The overall aim of this program is to develop models for enzyme replacement therapy and lysosomal storage diseases and to test the efficacy of enzyme replacement in deficient human subjects. The program includes studies of lysosomal enzyme biogenesis in the rat, studies of intracellular protein transport, characterization of the multiple forms of Beta-glucuronidase in man, studies of the uptake distribution and fate of different forms of purified human and Beta-glucuronidase in cultured cells, in animals, and in man, and studies of the clinical response and the immunological response to infused enzyme in deficient human subjects. Project I deals with the clinical, animal, and cell culture studies of lysosomal enzyme replacement. Project II deals with immunologic studies of enzyme replacement therapy. Specifically, Project II aims to characterize the enzyme-deficient patients on the basis of whether they possess antigenically cross-reactive material and to study the immune response to infused enzyme in deficient patients. Project III focuses on the elucidation of factors which influence the uptake and biosynthesis of Beta-glucuronidase in cultured cells and in the whole rat. Project IV aims to elucidate the mechanisms involved in the biosynthesis and secretion of two proteins in the liver: serum albumin and alpha-l-antitrypsin. Project V aims to isolate, purify, and characterize the forms of Beta-glucuronidase present in human platelets and human placenta and to provide structural evidence for the basis of lysosomal enzyme uptake by detailed analysis of the two forms of Beta-glucuronidase which demonstrate the biological difference of recognition or non-recognition by cultured human fibroblasts. BIBLIOGRAPHIC REFERENCES: Bell, C. E., Sly, W. S., and Brot, F. E.: Human beta-glucuronidase deficiency mucopolysacchariosis. Identification of cross-reactive antigen in cultured fibroblasts of deficient patients by enzyme immunoassay. J. Clin. Invest. 59, 97-105, 1977. Frankel, H. A., Glaser, J. H., and Sly, W. S.: Human beta-glucuronidase I. Recognition and uptake by animal fibroblasts suggest animal models for enzyme replacement studies. Ped. Res. In press. 1977.